Field of the Invention
The present invention relates to a grass mower.
Background Art
A vehicle described in U.S. Pat. No. 8,042,322 B1 is provided with a mower deck, a plurality of rotating shafts supported side-by-side in the mower deck and extending in the vertical direction, and cutting blades respectively fixed at lower ends of the rotating shafts. An electric motor for rotationally driving each cutting blade is mounted between two rotating shafts in the upper wall face of the mower deck. An output shaft of the electric motor extends in the horizontal direction toward each rotating shaft from both lateral sides of the electric motor. Each output shaft and each rotating shaft are respectively linked with bevel gears. Each cutting blade is rotationally driven by the electric motor. When this sort of configuration is adopted in a mower provided with a mower deck installed to a vehicle body such that ground height can be changed through a raising/lowering mechanism, for example when raising/lowering the mower deck, there is a risk that the electric motor, bevel gears, or the like protruding upward from a ceiling wall of the mower deck will interfere with the vehicle body, so it is difficult to adequately secure the ground height of the mower deck. On the other hand, when the height of the vehicle body is set too high in order to secure the ground height of the mower deck, the problem occurs that the center of gravity of the vehicle becomes high.
Also, a lawn tractor (lawn mower) described in U.S. Pat. No. 8,191,343 B1 is provided with a mower deck having three cutting blades disposed in a row. An output shaft of an electric motor is linked to an upper end of a center rotating shaft having a center cutting blade installed to its lower end. A left rotating shaft to which a left cutting blade is installed, and a right rotating shaft to which a right cutting blade is installed, respectively, receive power from the center rotating shaft through belt transmission. The electric motor that rotationally drives each cutting blade is disposed at a highest position of the mower deck. A controller that supplies electric power to the electric motor is disposed in an area surrounded by the center rotating shaft, the left rotating shaft, and the right rotating shaft on the ceiling wall of the mower deck. The ground height of the controller is less than the ground height of the electric motor. In this lawn tractor as well, the electric motor is disposed at the upper end of the center rotating shaft, so for example when raising/lowering the mower deck, there is a risk that the electric motor or the like will interfere with the vehicle body, so it is difficult to adequately secure the ground height of the mower deck.
Also, an electric lawn mower described in U.S. Pat. No. 8,572,939, B2 is provided with a mower deck having three cutting blades disposed in a row. Electric motors corresponding to the respective cutting blades are disposed at upper ends of rotating shafts of all of the cutting blades. Power supply to each electric motor is performed by a power supply system including an inverter and a battery mounted in a vehicle body. In this electric lawn mower as well, for example when raising/lowering the mower deck, there is a risk that each electric motor or the like will interfere with the vehicle body, so it is difficult to adequately secure the ground height of the mower deck.
As described above, in a conventional mower deck, a cutting blade driving device having height, such as a gear mechanism or an electric motor, is disposed on the upper part of a rotating shaft of a cutting blade. Therefore, it is difficult to adequately secure the raising/lowering stroke of the mower deck.
For the reasons as described above, a grass mower is desired in which an adequate space can be secured between the bottom of a vehicle body and a rotating shaft of a cutting blade supported by a mower deck.